Problem: Simplify the expression. $(n-4)(-n-4)$
Answer: First distribute the ${n-4}$ onto the ${-n}$ and ${-4}$ $ = {-n}({n-4}) + {-4}({n-4})$ Then distribute the ${-n}.$ $ = ({-n} \times {n}) + ({-n} \times {-4}) + {-4}({n-4})$ $ = -n^{2} + 4n + {-4}({n-4})$ Then distribute the ${-4}$ $ = -n^{2} + 4n + ({-4} \times {n}) + ({-4} \times {-4})$ $ = -n^{2} + 4n - 4n + 16$ Finally, combine the $x$ terms. $ = -n^{2} + 0 + 16$